In the past, sulfurized sperm oil has been used as an additive in many lubricant formulations such as in gear oils, worm, and spur gears, automatic transmission fluids, way lubricants and as a metal working additive. Sperm oil has now become restricted and the present invention is directed to an improved replacement therefor. The present invention is directed to an improvement over the invention described and claimed in United States Patent Application Ser. No. 220,399, filed Jan. 24, 1972 by Alexander D. Recchuite, which relates to a substitute for sulfurized sperm oil. This substitute is prepared by cosulfurizing an olefin and a triglyceride. This product exhibits improved solubility in paraffinic oils over sulfurized triglycerides, while retaining the lubricity properties of such sulfurized triglycerides.